Collaborative Research: Genesis of Primitive, High-Sr Lavas in the Western Aleutians

学术价值：这项研究是四个机构的合作，支持2005年7月至8月进行的一次巡航期间在阿留申西部海底疏浚火山所收集的火山岩的地球化学研究。初步结果表明，这些岩石中含有大量的原始熔岩，其中不仅包括玄武岩，还包括具有不寻常微量元素组成的安山岩和英安岩。该项目的目标是分析100个这样的样品，并使用这些数据来模拟导致其成因和演化的岩石学和地球化学过程，并将这些结果置于俯冲带岩浆过程的背景下。分析工作将集中在包括常量和微量元素在内的全岩地球化学上，测定100个样品中的部分样品的铅、锶、钕和氢同位素比值，对一些最新鲜的含玻璃熔岩中的斑晶和玻璃包裹体进行电子探针研究，并使用离子探针测定辉石斑晶和以橄榄石和辉石为主体的玻璃包裹体的微量元素组成。华盛顿卡内基研究所的一名合作者将对玻璃夹杂物中的挥发性和轻质元素进行一项小型、免费的初步研究。更广泛的影响：这项研究涉及四个机构之间的合作，将支持南卡罗来纳州一所大学的一名博士生和本科生。南卡罗来纳州是EPSCoR州。该项目还聘请了一名新的海洋科学研究人员。地球化学分析将支持共享使用的分析设施，从而帮助维持科学的基础设施。数据将被存档，并在众所周知的地球化学数据库上向公众提供，包括GeoRock和PetDB。

Intellectual Merit: This research is a four-institution collaboration that supports geochemical studies of volcanic rocks collected by dredging volcanic the western Aleutian seafloor during a cruise carried out in July-August 2005. Preliminary results show that the rocks contain a large proportion of primitive lavas that include not only basalts, but also andesites and dacites with unusual trace element compositions. Goals of the project are to analyze 100 of these samples and use the data to model the petrological and geochemical processes leading to their genesis and evolution and placing these results in the context of subduction zone magmatic processes. Analytical efforts will focus on whole-rock geochemistry including major and trace elements, determine Pb, Sr, Nd and Hf isotopic ratios on a subset of the 100 samples, carry out electron microprobe studies of phenocrysts and glass inclusions in some of the freshest glass-containing lavas, and use the ion probe to determine trace element compositions of pyroxene phenocrysts and glass inclusions hosted by olivine and pyroxene. A small, no-cost pilot study of volatile and light elements in glass inclusions will be carried out by a collaborator at the Carnegie Institution of Washington. Broader Impacts: This research involved collaboration between four institutions and will support a PhD student and undergraduates at a university in South Carolina, which is an EPSCoR state. The project also engages a new investigator in ocean science. Geochemical analyses will support shared use analytical facilities thereby helping sustain the infrastructure for science. Data will be archived and made available to the public on well know geochemical databases, including GeoRock and PetDB.